Lobanz
Bronze Member
- Joined
- Oct 16, 2011
- Messages
- 99
- Tractor
- Kubota L3400, Kubota G5200H
Xcellent! Now you're beginning to see the big picture. Clogged primary fuel filter causing lack of fuel delivery to lift pump/IP and injectors, of which all suffered in one way or another. Lean fuel delivery causing overheating when tractor being worked hard with dull bladed mower and high grass, etc.
How tractor ran at all is beyond understanding, but I'd bet you were saving big time on fuel use!
Yes. I was thinking about that -- how all these systems are interrelated: cooling, fuel, air, lubrication, etc. Seems like on smaller engine like this, there may be less margin for error -- especially when your cooling system only holds 2.2 QUARTs. The tiny cooling system has to be in perfect working order and nothing else can cause any extra heat.
I could be wrong, but, I'm not convinced that a diesel engine can overheat by running too lean. There is no throttle body to limit the air flow, so it's always gulping as much air as possible -- there is always an excess of oxygen in the combustion chamber during normal running conditions. Black smoke indicates incomplete combustion (i.e., too much fuel, or too little air), so it seems that if it ain't smokin', then it's getting full combustion. So, the impact of being starved for fuel would be loss of power and, eventually, stalling (i.e., so little fuel that combustion does not produce enough energy to overcome load), but WITHOUT black smoke. This jives with the fact that when my mower had the fuel restriction, there was no black smoke when it stalled under light load. The reason why there is black smoke when a sudden load is encountered is that the governor somehow senses the load (drop in RPMs but no drop in throttle position?) and squirts in more fuel resulting in a temporary over fueled condition. In a short time, the RPMs come up and the governor is satisfied and backs off the fuel and the smoke goes away. This is also the reason that there is a little black smoke when I punch the throttle even under "no load". By punching the throttle, I've told the governor that I want to increase engine RPMs. The "load" is just the inertia of the engine parts that take energy to being them up to speed (flywheel, etc, maybe the whole tractor if I'm driving). If there is constant black smoke, it would mean that there is a constant condition of too much fuel for the air being taken in, meaning that either the air intake is restricted, or that the load is too much for the engine to handle (governor is squirting in as much fuel as it can but RPMs are not coming back up), or something is malfunctioning or ain't adjusted right causing either too much fuel or incomplete combustion (governor adjustment, injection pump adjustment, injectors not spraying right, injection timing adjustment, maybe other things). Is this a correct understanding?
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